CCF analysis for new reactor designs
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J. Blombach
Abstract
Common Cause Failures (CCF) have been an issue of safety consideration in nuclear safety since a long time. For the design of the European Pressurised Reactor (EPR) probabilistic safety goals in conjunction with the limit set by CCF on failure probability that can be achieved by redundancy led to the requirement to fulfil vital safety functions by functionally diverse systems. The probabilistic safety analysis (PSA) which was performed for EPR takes into account CCFs which are modelled using the beta-factor model of the European Utility Requirements (EUR). The PSA shows that the probabilistic safety goal for core damage frequency – CDF < 10−5/year – is met with sufficient margin. In addition to the modelling of CCF in the PSA a deterministic CCF analysis is being performed. It is a safety function based approach on component level analysing frontline and backup systems with respect to common components or type identical components. It ensures that diverse safety functions are fulfilled by systems being sufficiently diverse including all necessary support systems. Components are identified where further diversification or additional defences against CCF are required.
Kurzfassung
Common Cause Fehler (CCF) (Gemeinsam Verursachte Ausfälle) sind seit langem Gegenstand sicherheitstechnischer Überlegungen in der kerntechnischen Sicherheit. Probabilistische Sicherheitsziele und die Erkenntnis, dass die Verringerung der Ausfallwahrscheinlichkeit durch Redundanzerhöhung durch CCF begrenzt ist, führten für den EPR zu der Auslegungsanforderung, wesentliche Sicherheitsfunktionen durch funktional diversitäre Systeme zu erfüllen. Die für den EPR erstellte probabilistische Sicherheitsanalyse (PSA) berücksichtigt CCF gemäß dem Beta-Faktor-Modell der EUR. Die PSA zeigt, dass das probabilistische Ziel für Kernschadenshäufigkeit – CDF < 10−5/a – mit Abstand eingehalten wird. Zusätzlich zur Modellierung von CCF in der PSA wird eine deterministische CCF Analyse durchgeführt. Dabei werden für eine Sicherheitsfunktion das Haupt- (frontline) und das Ersatzsystem (backup) auf Komponentenebene daraufhin untersucht, ob es in beiden Systemen gemeinsame oder typidentische Komponenten gibt. Die Analyse stellt sicher, dass diversitäre Sicherheitsfunktionen durch hinreichend diversitäre Systeme erfüllt werden. Komponenten, für die weitere Diversifizierung oder Maßnahmen gegen CCF erforderlich sind, werden identifiziert.
References
1 KTA 3501 „Reaktorschutzsystem und Überwachungseinrichtungen des Sicherheitssystems“Search in Google Scholar
2 BMI Kriterium 5.3 „Einrichtungen zur Steuerung und Abschaltung des Kernreaktors“, RSI 6-51330-1/9, Bonn, 21. 10. 1977Search in Google Scholar
3 EUR, European Utility Requirements Revision C, 1991Search in Google Scholar
4 GPR/94-50: Conclusions of the common GPR/RSK meetings of September 12th, 1994 and October 11th, 1994Search in Google Scholar
© 2006, Carl Hanser Verlag, München
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Editorial
- Common cause failure analysis within the framework of probabilistic safety assessment
- Technical Contributions/Fachbeiträge
- Updated requirements on PSA methods and data for comprehensive safety reviews in Germany
- OECD/NEA International Common Cause Failure Data Exchange (ICDE) Project – insights and lessons learnt
- Protection against dependent failures, analysis of dependencies and derivation of CCF data
- Extension of the German database for common cause failure events
- International network on incorporation of ageing effects into PSA
- CCF analysis for new reactor designs
- CCF treatment in PSA: insights and recommendations from reviewing procedures
- Is mapping a part of common cause failure quantification?
- Further development of the coupling model
- The Process-Oriented Simulation (POS) model for common cause failures: recent progress
- CCF analysis in PSA applications from a licensee view
- Notes
- Radiation protection of outside workers
- Technical Contributions/Fachbeiträge
- Occupational exposure to natural radiation
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Editorial
- Common cause failure analysis within the framework of probabilistic safety assessment
- Technical Contributions/Fachbeiträge
- Updated requirements on PSA methods and data for comprehensive safety reviews in Germany
- OECD/NEA International Common Cause Failure Data Exchange (ICDE) Project – insights and lessons learnt
- Protection against dependent failures, analysis of dependencies and derivation of CCF data
- Extension of the German database for common cause failure events
- International network on incorporation of ageing effects into PSA
- CCF analysis for new reactor designs
- CCF treatment in PSA: insights and recommendations from reviewing procedures
- Is mapping a part of common cause failure quantification?
- Further development of the coupling model
- The Process-Oriented Simulation (POS) model for common cause failures: recent progress
- CCF analysis in PSA applications from a licensee view
- Notes
- Radiation protection of outside workers
- Technical Contributions/Fachbeiträge
- Occupational exposure to natural radiation
